JVM version detection chokes on "17-internal"

[Hamlin-Li]

Hi,
Can you have a look at this minor issue? This is to bring mior improvement to the sbt script.
I'm working on to support riscv for zstd-jni, please check [2], during the process, I found out that currently sbt script support GA/EA release of jdk, but not internal jdk, but for riscv jdk, most of time people still working on internel version of jdk during developement process. So it's helpful to support the internel version of jdk.

At first I bring the patch to zstd-jni [1], luben (zstd-jni author) think it's better to bring the patch here.

Thanks!

[1] luben/zstd-jni#280
[2] luben/zstd-jni#282